Both. The Mobil is $22.37 on Amazon, $29.79 on Rock Auto.
I saw the Mobil 1 last week at NAPA, and both the Quaker State and Mobil 1 at Walmart. The QS was under $20 for 5 quarts.
The oil I've been using in my stock 340 was recently discontinued, so I started researching a replacement. These two will do fine, and I'm sure there are others. I'm planning to use the QS, because their parent company sends me a check every month to not work. :D
